Dear Altruists, 

I would like to mirror all the items of a pattern with respect to a plane. For doing this I require to select each of the items of the pattern one by one which is a tedious and troublesome issue for my complex drawing with a large number of items in the pattern in my actual project. I was thinking is there any way to select all the items of a pattern at once?

I tried a way, i.e, dragging the cursor clicking the left button of the mouse but in my actual project where many intermediates objects also get selected.